This invention relates to polymer compositions which contain a normally flammable and/or poorly flame retardant olefin polymer, elemental phosphorus and halogenated organic moiety.
By reason of their favorable physical properties and relatively low cost, olefin polymers have been used for most widely diverse applications including applications as solid molding materials and as foamed compositions.
In recent times, it has become increasingly important to impart flame resistant properties to olefin polymers. This is particularly true where solid olefin polymers are used as insulating material in the electrical industry and where foamed olefin polymers are used as insulation and to prevent risk of fire in the daily use of other items.
It has been proposed heretofore to impart flame-retardancy to an olefin polymer by incorporating various additives into the polymer. Flame-retardance has been obtained, for instance, by combining with the polymer a solid chlorinated hydrocarbin, e.g., chlorinated paraffin, with a flame-retardant inorganic oxide, preferably antimony oxide, in critical proportions to each other and to the polymer. Such compositions are described in U.S. Pat. Nos. 2,480,298, 2,590,211 and 2,669,521.
In view of the relatively high cost and possible ecological hazards of antimony oxide and the substantial amounts by weight which must be employed to impart reduced burning characteristics to olefin polymers, it would be highly desirable to provide a more economical and non-toxic means for reducing the propensity of olefin polymers to propagate combustion after a low scale ignition source has been removed.